Disk-grinder attachment



G. R. BARKSDALE.

DISK GRINDER ATTACHMENT. APPLICATION FILED Nov.19. 1920.

1,419,535 a Patented June 13, 1922.

2 SHEETS-SHEET L FEE 11- WITNESS: q

GEORGE R. BARKSDALE, 0F STRATFORD, ONTARIO, CANADA.

DISK-GRINDER ATTACK-1M ENE.

Application filed. November 19, 1920. Serial No. 425,246.

To (all 101 10722 it may concern:

Be it known that l, Gnonen R. Blinksnarnn, a citizen of the UnitedStates of America, residing at Stratt'ord, in the county ot Perth,Province of Ontario, and Dominion of Canada, have invented a new anduseful Dislclrrinder Attachment, of which the following is aspecification.

liiiy invention relates to improvements in attachments for diskgrinders, and consists generally of a rotatable and reciprocable shaftprovided with certain peculiar work-holding means, and certain peculiarmeans or mechanism for controlling and operating said shaft, all ashereinafter set forth.

The primary object of my invention is to provide a comparatively simpleand inexpensive, yet strong and durable, attachment for use inconnection with grinders ot the class specified above, whereby a largeproduction at a low cost, and an excellent grade of work well, areobtained, and wherewith the pressure of the casting being ground on thegrinding disk can be kept uniform and as great as may be desired. litthe pressure he too light, the abrasive material on the grinding diskbecomes glazed, since in that case it cannot clear itselt oi": the smallparticles produced by the triction incident to the grinding operation.and the abrasive eitect of said disk is greatly reduced. The life of thegrinding disk is, therefore, prolonged by the use or my attachment, andthis may be said to constitute another object of my invention.

A further object is to atl'ord means whereby is entirely obviated theliability at too forcibly thrusting the casting to be ground against thegrinding disk and thereoy seriously damaging the disk or its abrasivematerial.

The holder .vith which my attachment is equipped is adapted toaccommodate castings having irregular shapes, and the attachmenta wholeis capable of being used with all types of disk grinders.

The operator who uses this attachment is relieved of the strain whichhas insome cases heretofore existed in connection with grinding on adisk grinder, so that a girl ran with said attachment do the work whichfrequently has required the services of a man.

The attachment is adjustable so as to enable work of any thicknessdesired to be ground, within certain regular or natural limitations.

Other objects and advantages will appear in the course of the followingdescription.

A preferred embodiment or" the invention, whereby l attain the objectsand se cure the advantages of the same, is illustrated in theaccompanying drawings, and I will proceed to describe the invention withreference to said drawings, although it is to be understood that theform, construction, arrangement, etc. of the parts in various aspectsare not material and may be modified without departure from the spiritof the invention.

In the drawings, in which like numerals designate like parts throughoutthe several views, Figure 1 is a central, longitudinal, vertical sectionthrough a disk-grinder attachinent which embodies a practical form ot myinvention as aforesaid, the disk of the attachn'icnt and the holderscarried thereby being in elevation; Fig. 2, a side elevation of theworking face of the cam; Fig. 3, a detail, in section, of the pistonhcadterminal oi? the shaft and associated parts and members, showing aspring substituted tor the compressed-air means whereby the cam on saidshaft is retained in contact with the abutments therefor; Fig. i, atransverse, vertical section through said attachment, taken on linesl-4, looking in the direction oi the associated arrow, in Fig. 1; Fig.5, an enlarged, exterior, broadside elevation of one of the workholders, and, Fig. 6, a central, transverse, vertical section hroughsaid work holder, on lines 6*6, in tl direction of the associated arrow,Fig. 5, a fragment of the disk to which said holder is attached alsoappearing.

Although I have shown as the preferred form pneumatic or compressed-airmeans for urging the reciprocable members forward and retaining the camon the revoluble and reciprocable shaft in yielding contact with theabutments provided therefor, it is obvious that a spring might beutilized for the same purpose, but it is equally obvious that yieldingmeans of the character of a spring would be much less ellicient thanyielding means ot the pneumatic type, and that it would be much morediflicult to change r adjust the amount of compression to meet differentconditions in the case of the former than in the case of the latter, itbeing much easier to adjust the reducing valve in a compressed-air linethan to take out a spring and insert a weaker or a stronger one, as thecase may be, in the place of the first. Nevertheless, 1 do not wish tobe confined exclusively to the pneumatic control or yielding means forthe reciprocating members, and will make use of a spring if for anyreason it appears to be desirable to do so.

I have shown the work-holder disk equipped with three work holders, andmost frequently such will be the number employed, although in some casesit may be desirable to use less and in other cases even more than thatnumber. Ordinarily, if more than three work holders were provided on thedisk, the castings held by such holders would not remain a sufficientlength of time in contact with the abrasive material of the grindingdisk to enable such castings to be properly ground, and limitation to asingle work holder would materially reduce the speed efliciency of theattachment.

Referring to the drawings, it will be observed that my attachmentcomprises a suitable supporting frame 1 having at the top bearings 22,with bushings 55 therein, the space between said bearings extendingdownwardly to form a cleft 7 in said frame, and the latter having alsoon top a seat 3 for a cylinder 8; a horizontal shaft j ournaled in saidbushings and extending into said cylinder, the right-hand terminal ofsaid shaft being in the cylinder, since the latter is at the right ofsaid bearings; a wormwheel 10 mounted on said shaft; a piston on theterminal of said shaft which is in said cylinder, and a work-holder disk11 on the opposite terminal or end of said shaft; a cam 12 secured tosaid shaft between the inner end of said cylinder and the adjacent endof the right-hand bearing 2; a plurality of abutments for said cam, andan equal number of holders on said disk. There are three cam abutmentsin the present case, although such number may vary and in any eventshould agree with the number of work holders, of which latter there arethree in the present case, as hereinbefore observed.

The worm-wheel 1O revolves through the cleft 7 in the frame 1, and thecam 12 revolves through a recess 18 with which said frame is furtherprovided. The wormwheel 10 is driven in the usual manner, and in turndrives the shaft 9 and with it the disk 11 and the work attached theretoand carried thereby. The shaft 9 is not only revolubly but alsoreciprocably mounted or journaled in the bearings 2 or the bushings 5therein, the reciprocating movement of said shaft being permittedbyreason of the fact that the hub of the worm-wheel 10 fits between thebearings 2 and bushings 5,

and said worm-wheel or hub is secured to said shaft by means of a key145 which is seated in said shaft and extends into a longitudinal slot15 in said hub, (a portion of the shaft being broken away in Fig. 1 toshow said key in full.) said slot being longer than said key, andextending beyond the same at both ends. A limited amount of axialmovement is thus permitted to the shaft 9 without interference therewithon the part of the worm-wheel 10, although the two members are connectedso that they must revolve together.

The inner end of the cylinder 8 is closed by means of a stuffing-box 16which is tapped into such end, a gland 17 which is tapped into the inneror open end of said stuffing-box, and stuffing 18 in the stuffingbox.Thus the terminal of the cylinder, which is around the terminal of theshaft 9 that extends into said cylinder, is securely closed. There is anopening in the center of the outer, closed end of the cylinder 8 for theintroduction into said cylinder of compressed air through a pipe 19 thatforms part of a compressed-air line or system. In the top of thecylinder 8 is an opening for a pipe 20 through which oil may beintroduced into said cylinder, and in the bottom of said cylinder is anopening for a pipe 21 through which oil may be drawn out of thecylinder.

The piston on the piston-head of the shaft 9, to which reference hasbeen made, com prises a supporting disk 22 and a cup-packing 23 securedto said piston-head by means of a bolt 24:. The end of the shaft 9 whichis in the cylinder 8 is turned down to form a projection or hub 25 onwhich the supporting disk 22 is mounted, and the bolt 24: is tapped intoand through said projection and into the main body of the shaft.

From the foregoing it is clearly to be seen that air under compressionin the cylinder 8 between the closed or outer end of said cylinder andthe cup-packing 25 or in other words, behind said cup-packing, tendsconstantly to urge the piston, of which said cuppacking constitutes apart, to the left, and with it the shaft 9 and the parts and membersthat are rigidly attached to said shaft. The force exerted on the pitonby the compressed air in the cylinder 8 may be varied in the usualmanner, just as in any other compressed-air apparatus which is providedwith a reducing valve.

Neither the compressed-air anparatus, system, or line, or the drivingmeans for the worm-gear 10. is herein shown, since both are mechanicalelements so well understood as to need no illustration, and inasmuch asthey constitute no direct part or element of or in the presentinvention.

Oil is introduced through the pipe 20 into the cylinder 8 to preventleakage of air therefrom, and may be drawn out of said cylinder throughthe pipe 21 Whenever occasion demands.

The cam abutments, of which mention has been made, consist of threehorizontal rods 26 provided with a corresponding number of rolls 27.Each rod 26 is tapped into and through a lug 28 which is integral withthe inner or right-hand bearing 2, and has thereon at each end of saidlug a nut 29 to secure said rod in place and permit the same to belongitudinally adjusted. And each rod 26 is provided at the right-handend with a bifurcated head 30 connected with which is one of the rolls27, such roll being mounted on a spindle 31 which is journaled ormounted in the arms of said head, and is radial to the axis of the shaft9. The lugs 28 are equi-distant from each other and the rods 26 are soarranged or adjusted in said lugs that the peripheries of the rolls 27,behind or at the right, touch a common vertical plane. The cam 12 is inoperative position relative to the rolls 27, and said cam has on and inthe working face thereof, which is the face or side that is adjacent orcontiguous to said rolls, three elevations 32 and the same number ofdepressions 33, The elevations 32 and consequently the depressions 33are equi-distant apart on the working face of the cam 12, and saidelevations are all alike, as are said depressions. The rolls 27 aspreviously stated, are equi-distant apart in the circle in which theyare located, which circle is concentric with the cam 12 and the shaft 9.The cam 12 is secured to the shaft 9, in proper position relative to theabutments, by means of a horizontal key 34, and a tapered pin or key 35that is driven into and through said shaft outside of or behind saidcam, or contiguous to the face of said cam which is opposite to theworking face of the same. The key 35 backs up the cam 12, so to speak,and thus reinforces the cam and insures the required stiffness thereoffor a firm contact with the abutment rolls 27. In this case the camfollows the rolls 27 and moves axially, instead of the rolls, as theyenter and leave the depressions 33 in the cam, being themselves causedto move in a direction other than that taken when revolving on theiraxes, and to carry with them the parts with which they are connected. Inshort, here the cam abutments, which take the place of ordinary camfollowers, remain stationary, except that their anti-friction membersrevolve, and the cam moves on its axis lengthwise, besides turningthereon, which is just the opposite of the usual arrangement andoperation of cam mechanism.

The compressed-air in the cylinder 8 behind the piston forces the shaft9 to the left or forward and causes the cam 12 ta,

remain in constant contact with the cam abutments, and to reciprocate asthe high and low parts of said cam ride over the rolls 27, with theresult that said shaft is reciprocated accordingly. The shaft 9 bothrotates and reciprocates in the stuffing-box 16 and associated parts orelements and carries with it whatever parts and members are rigidlyattached thereto.

The work-holder disk 11 has a hub 36 and these are rigidly attached tothe lefthand or what may be termed the forward end of the shaft 9 andare located beyond the corresponding end of the frame 1. I will nextproceed to describe in detail one of the three work-holders with whichthe disk 11 is equipped, it being understood that any of saidwork-holders is the duplicate of either of the others, and that they arearranged equi-distant apart on the outer or front face of said disk.

Secured to the inner or backside or face of the disk 11 adjacent to theperiphery thereof, by means of a pair of bolts 37, is a plate 38. Formedpartly in the center of the plate 38 and partly in the disk 11 is arecess 39. A passage 40 extends outwardly or forwardly from the recess39, or that part of the same which is in the disk 11, to and through theoutside or front face of said disk. A bolt 41 has a globular head 42which is received in the recess 39, and a shank that extends through thepassage 40 and some distance beyond the outer face of the disk 11. Thediameter of the passage 40 is somewhat larger than that of the shank orthat portion of said shank, of the bolt 41, which is located in saidpassage, but there is a felt washer 43 which encircles such shank andtends to retain the same in a horizontal position, said washer beingheld in place or secured between the outside face of the disk 11 and aperforated disk or ring 44, by means of two or more bolts 45 that passthrou h said ring and washer and are tapped into said disk. Arectangular block 46 is screwed on to the outer terminal of the bolt 41.Rigidly secured, by means of rivets 47, to the outer face of the block46 adjacent to the lower corners thereof are two fixed dogs 48. Amovable, angular dog 49 is located in a slot 50 in the center of theupper part or portion of the block 46, which slot is radial to the axisof the disk 11. The dog 49 has an overhanging head 51, the sameprojecting beyond the outer face of the block 46. A face-plate 52 issecured, by means of screws 53, to the block 45 over the dog 49 infront. The overhanging portion of the head 51 of the dog 49 extendsbeyond the face-plate 52. A spring 54 is arranged in a passage in theblock 46 and a recess in the bolt 41, provided to receive said spring,to bear against the inner end of the dog 49, and to force said dogoutwardly. The block 46 is provided behind the body portion of the dog49 with a stud 55, and mounted on this stud is an eccentric 56, saideccentric beingheld in place on said stud, against the back sides orback edges of the slot 50, by means of a screw 57 which is tapped intosaid stud from the rear or inner end thereof, and has a head largeenough to extend onto or engage said eccentric. The eccentric 56 is incontact with a rearwardly-extending arm 58 at the inner terminal of thedog 9, and is adapted to actuate said arm and dog inwardly against theforce of the spring 54, or to permit said spring to actuate said dogoutwardly, according to the direction in which said eccentric is rotatedon its stud 55. The eccentric 56 is provided with peripheral openings 59for the introduction of a bar or red (not shown) when said eccentric isoperated.

Inasmuch as the bolt 41 has some movement on its head 42 which is in therecess 39, and due to the fact that the diameter of the passage 40 issomewhat larger than the diameter of that portion of the shank of thebolt that is in said passage, a certain amount of movement is permittedto the block 46 carried at the outer end of said bolt. The fibrouswasher 43 yields to permit the bolt 41 to rock, and said washer is,therefore, another factor in the independent rocking or oscillatorymovement of said bolt. The aforesaid movement permits the block 46 torock and properly adjust itself with the work attached thereto to thegrinding disk. A yielding support is provided between the block 46adjacent to its inner end and the disk 11, such support being in theform, in this case, of a spiral spring 60 interposed between said block.and said disk, or rather between the head of a rod 61, which head bearsagainst said. block, and said disk. The headed rod 61 is slidinglymounted in the disk 11, parallel with the axis of said disk, behind theblock 46 near the inner end of the longitudinal center thereof, and thehead of said rod is thrust into engagement with said block by the spring60, the outward or forward movement of the rod being limited. by atransverse pin 62 therein behind said disk. The spring 60 encircles therod 61 between the head and the disk 11, and the pin 62 limits theoutward or forward movement of said rod under the influence of saidspring. The pin 62 is so placed. or located in the rod 61 that the block46 is positioned in substantially parallel relation with the disk 11,when said pin is in contact with the back side of said disk. The blockmay be forced inwardly, against the resiliency of the spring 60, at theinner end, the bolt 41 then rocking on its head 42 and overcominwhatever resistance may be offered by the felt washer 43. As soon as theirregular pressure is removed from the block 41, the spring 60 acts torestore the parts to normal position again. Only a slight amount ofmovement is thus provided for, but the same is suflicient to enable theblock 46 with the work carried on the face thereof automatically toadjust itself to the grinding-wheel disk. Inasmuch as the block 46 isnot attached to the rod 61, said block may be rocked on and with thebolt 41 in the direction to carry the inner end of said block away fromsaid rod in which event the rod, being spring-pressed, serves as abuffer for the block when it returns to normal position.

The broken lines at 63 represent a piece of work or a casting carried byeach holder. The casting 63 has a fiat-iron shape, and is arranged withits apex end towards the axial center of the disk 11 and between thedogs 8, and its broad end or base within the grasp of the projectinghead 51 of the movable dog 49. The casting is thus located after firstrotating the eccentric 56 on its stud 55 in the direction to enable thespring 54 to throw the dog 49 outwardly a sufiicient distance to permitsaid casting to be placed flat against the face of the block 46. Whenthe casting 63 is located againstthe face of the block 46, in the mannerjust described, the eccentric 56 is actuated in the opposite directionto force the dog 49 inwardly against the resiliency of the spring 54,and crowd the head 51 of said dog tightly against the base of saidcasting. Thus the work is held with absolute security between the fixeddogs 48 and the movable dog 49.

Pins 6767 are set in the face of the disk 11, on opposite sides of eachplate 46, to hold said plate and the bolt 41 against rotary motion aboutor on the axis of said bolt. The plate 46, with the bolt 41, is,therefore, limited to a rocking motion or movement, between thecontiguous pins 67, on the bolt head 42 in the recess 39.

In practice, the castings 63 are attached to the work holders, the poweris applied to the worm-wheel 10 to revolve said wormwheel and the shaft9, each of said castings is thrust into contact with the grinding diskor wheel (not shown) and permitted to re main the required length oftime to grind the exposed surface or the face of such casting. and thenthe latter is withdrawn from said wheel. The castings, being secured bythe work holders to the disk 11, revolve with said disk as the latter isrotated with the shaft 9, and each time that the low parts of the cam 12contact with the abutment rolls 27 the pressure in the cylinder 8 behindthe piston forces said piston, the shaft 9, and the disk 11, with thework holders attached thereto and the castings carried by said holders,forward, thus projecting, said castings into the plane of the aforesaidgrinding wheel and one of the castings into contact with said wheel.When the elevations 82 of the cam 12 ride on to the abutment rolls 27,said cam is forced rearwardly and carries with-it, against the aforesaidpressure in the cylinder 8, the shaft 9 with its piston at one end anddisk at the other end, and so withdraws the castings from the grindingwheel and the grinding wheel plane. The cam 12 is so constructed andproportioned as to allow each casting to remain in contact with thegrinding wheel or the grinding surface thereof long enough to completethe grinding operation on such casting, that is to say, to grind theexposed surface of said casting to the required extent.

Inasmuch as it is desired to bring the castings 63 snugly into contactwith the grinding wheel, the driving and reciprocating mechanism for theshaft 9 are necessarily so proportioned relatively, or timed, that saidshaft, with the disk 11, work holders, and work, is advanced andretracted three times at each revolution. A different timing andarrangement might be employed, and the arrangement might be such thatall of the castings supported from the disk 11 would be groundsimultaneously.

If any casting were permitted to come gradually into contact with thegrinding surface or to encounter the edge of the grinding-wheel, it willbe readily seen that there would be grave liability of breaking offpieces of said wheel. or otherwise injuring the same or the grindingsurface thereof. This liability is entirely avoided by my mechanismwhich causes each casting to be thrust against the grinding wheel atjust the proper place and instant. and causes said casting to bewithdrawn at just the right time.

After the three castings 6-3 have been ground, the movable parts of theattachment are stopped, the eccentrics 56 are operated to release thecastings, the latter are removed, and others to be ground are placed inthe holders. The mechanism is then set in motion again and the grindingoperation repeated. This cycle of events may be repeated indefinitely.

The operation of releasing and removing from the work holders thecastings 63, and

placing other castings in said holders and securing them therein, can bedone most expeditiously as well as conveniently and easily.

In order to regulate the attachment to the thickness of the work, it issimply necessary to loosen the nuts 29, screw the abutment rods 26 inwhichever direction may be necessary to bring about the requiredadjustment, and retight'en said nuts. For a thicker casting, it isnecessary to adjust the abutment rods 26 to the right, so that the rolls27 will position the foremost and rearmost, operating plane of the cam12 and of all of the parts and members controlled by said cam farther inthat direction. Contrariwise, if it be necessary to set the mechanismfor thinner castings, the abutment rods 26 are adjusted to the left, sothat the rolls permit the aforesaid operating planes of the cam 12 andof the parts and members controlled thereby to be located farther insaid. last-named direction.

As previously intimated, a spring, as 6 may be substituted for thecompressedir in the cylinder 8 back of the piston, or back of what maytake the place of the complete piston when said spring is employed,namely, the supporting disk 22 of said pistonsee Fig. 3. The supportingdisk 22 is held in place by the same bolt 24 as before, a washer 65being interposed between the head of said bolt and adjacent parts.Obviously the movable parts and members of this attachment operate insubstantially the same man nor with the spring 64 as when compressedairis employed back of the piston head of the shaft 9. But it is equallyobvious that the spring 6 f does not afford the ready means of controland of varying the control of the reciprocable movement of the shaft 9and attached parts that is afforded by the compressed air. When thespring 64 is employed it is necessary either to construct the cylinder 8without any opening in the outer end for the compressed-air pipe 19, orto close such opening, as with a plug 66. The oil pipes 20 and 21 may ormay not be retained, as desired.

l'Vhat I claim as my invention, and desire to secure by Letters Patent,is

1. In an attachment, of the class described, a revoluble andreeiprocable shaft, a cam mounted on "said shaft, an abutment, andyielding means to retain said cam in contact with said abutment, saidshaft being provided with work-holding means.

2. In an attachment, of the class described, a revoluble andreciprocable shaft, a cam and work-holding means mounted on said shaft,an abutment, and yielding means to retain said cam in contact with saidabutment.

8. The combination, in an attachment of the class described, with aframe, and a cylinder and cam abutments supported by said frame, of ashaft journaled insaid frame, and extending into said cylinder, adriving member for said shaft, the latter being revolubly connected withsaid driv ing member, but having independent longitudinal movementrelative thereto, a cam secured to said shaft in operative relation tosaid abutments, said cylinder being adapted to contain yielding means toactuate said shaft in the direction to retain said cam in contact withsaid abutments, and work-l1olding means connected with said shaft.

4. The combination, in an attachment of the class described, with aframe, and a cylinder and cam abutments supported thereby, of a shaftiournaled in said frame, and extending into said cylinder, rotarydriving means for said shaft, a cam secured to said shaft in operativerelation to said abutments, said cylinder being adapted to containyielding means to actuate said shaft in the direction to retain said camin contact with said abutments, and work-holding means connected withsaid shaft, the mechanism being so timed that the shaft and at. tachedparts and members are reciprocated as many times as there are camchanges, at each revolution of the shaft.

5. The combination, in an attachment of the class described, with aframe, and a cylinder and cam abutments supported thereby, of a shaftjournaled in said frame, and extending into said cylinder, a drivingmember for said shaft, the latter being revolubly connected with saiddriving memher, but having independent longitudinal movement relativethereto, a cam secured to said shaft in operative relation to saidaluitments, a piston on the terminal of said shaft that is in saidcylinder, the latter being adapted to receive and contain compressedairbetween the head thereof and said pis ton, and work-holding meansconnected with said shaft.

6. The combination, in an attachment of the class described, with aframe, and a cylinder and cam abutments supported thereby, saidabutments being; adjustable, of a shaft journaled in said frame, ande);- tending into said cylinder, a driving, member for said shaft, thelatter being revolubly connected with said driving; member, but havingindependent longitudinal movement relative thereto, a cam secured tosaid shaft in operative relation to said abutments, said cylinder beingadapted to contain yielding; 11 cans to force said shaft in thedirection to retain said cam in contact with said abut-- ments, andwork-holdingmeans connected with said shaft.

7. ln an attachment, of the class described, a revoluble andreciprocable shaft provided with work-holding means, an adjustable camabutment, a cam mounted on said shaft, and yielding means to retain saidcam in contact with said abutment.

8. The combinatiom'in an attachment of the class described, with aframe, and a cylinder and cam abutments supported thereby, of a shaftjournaled in said frame, and extending into said cylinder, a drivingmember for said shaft, the latter being revolubly connected with saiddriving member, but having independent longitudinal movement relativethereto, a piston on the end of said shaft that is in said cylinder, astuffing-box for said shaft in said cylinder, said cylinder beingadapted to receive and contain com pressed-air behind said piston, acamsecured to said shaft in operative relation to said abutments, andwork-holding means connected with said shaft.

9. The combination, in an attachment of the class described, with aframe, and a cylinder and cam abutments supported thereby, of a shaftjournaled in said frame, and extencing into said cylinder, a drivingmember for said shaft, the latter being revolubly connected with saiddriving member, but having longitudinal independent movement relativethereto, a cam secured to said shaft in operative relation to saidabu'tments, a piston on the end of the shaft that is in said cylinder,the latter having inlets for compressed-air and oil behind said piston,a stuffing-box in said cylinder for said shaft, and worleholding meansconnected with said shaft.

10. The combination, in an attachment of the class described, with aframe having projections, and cam-abutment rods adjustably arranged insaid projections and provided with anti-friction members, of ashaftjournaled in said frame, means to rotate said shaft, a cam on saidshaft, and yielding means to urge said shaft in the direction to forcesaid cam into contact with said abutment rods, the latter being parallelwith said shaft.

11. The combination, in an attachment of the class described, with arevoluble and reciprocable shaft provided with a worleholder support,and. yielding means to actuate said shaft longitudinally in onedirection, of a rocking work holder attached to said support.

12. The combination, in an attachment of the class described, with arevoluble and reciprorable shaft provided with a workholder support, andyielding means to actuate said shaft longitudinally in one direction, ofa worlvholder carried by said support. said holder comprising a studprojecting from said support, a block supported by said stud, and meansto attach the work to said block 13. The combination, in an attachmentof the class described, with a revoluble and reciprocable shaft providedwith a workholder support, and yielding means to actuate said shaftlongitudinally in one direction, of a work-holder carried by saidsupport, said holder comprising a stud projecting from said support, ablock supported by said stud, and means to attach the work to saidblock, said stud being adapted to rock in said support.

14-. The combination, in an attachment of the class described, with arevoluble and reciprocable shaft, yielding means to actuate said shaftlongitudinally in one direction, and a work-holder support mounted onsaid shaft, of a work holder attached to said support, said holdercomprising a bolt having its head secured in said support, andprojecting therefrom, a block attached to the outer terminal of saidbolt, and yielding means to retain said block in approximately parallelrelation with said support.

15. The combination, in an attachment of the class described, with arevoluble and reciprocable shaft, yielding means to actuate said shaftlongitudinally in one direction, and a work-holder support mounted onsaid shaft, of a work holder attached to said support, said holdercompressing a bolt having its head confined in said support, andprojecting therefrom, the arrangement being such as to permit to saidbolt alimited amount of movement, a Washer of yielding materialencircling said bolt, means secured to said support to retain saidwasher in place, a block mounted on said bolt and provided with holdingmeans for the work, and yielding means to retain said block inapproximately parallel relation with said support.

16. The combination, in an attachment of the class described, with arevoluble and reciprocable shaft, yielding means to actuate said shaftlongitudinally in one direction, and a work-holder support mounted onsaid shaft, of a work holder attached to said support, said holdercomprising a bolt having its head in said support and capable of limitedmovement independently of said support, a block mounted on said bolt,said block being provided with work-securing means, a headed rodslidingly arranged in said support behind said block, a springinterposed between said support and the head of said rod, and means tolimit the outward movement of said rod.

17. The combination, in an attachment of the class described, with arevoluble and reciprocable shaft, yielding means to actuate said shaftlongitudinally in one direction, and a work-holder support mounted onsaid shaft, of a work holder carried by said support, said holdercomprising a bolt having its head in said support and capable of limitedindependent movement relative thereto, a yielding washer encircling saidbolt, means attached to said support to secure said washer in place, ablock mounted on said bolt, said block being provided withwork-attaching means, a headed rod slidingly arranged in said supportbehind said block, a spring interposed between said supportand the headof said rod, and means to limit the outward movement of said rod.

18. The combination, in an attachment of the class described, with arevoluble and reciprocable shaft, yielding means to actuate said shaftlongitudinally in one direction, and a work-holder support mounted onsaid shaft, of a work holder comprising a block carried by said support,and provided with fixed and movable dogs, the movable dog beingspring-actuated in one direction, and an eccentric arranged to actuatesaid movable dog against the force of its spring.

19. The combination, in an attachment of the class described, with arevoluble and reciprocable shaft, yielding means to actuate said shaftlongitudinally in one direction, and a work-holder support mounted onsaid shaft, said support having pins projecting therefrom, of a workholder carried by said support between said pins, and adapted to rocktherebetween.

20. The combination, in an attachment of the class described, with arevoluble and reciprocable shaft, yielding means to actuate said shaftlongitudinally in one direction, and a work-holder support mounted onsaid shaft, of a work holder comprising a block carried by said support,and provided with fixed and movable dogs, the movable dog beingspringactuated in one direction, and means to hold said movable dog andactuate the same against the force of its spring.

GEORGE R. BARKSDALE. Witnesses LELAND M. GILMAN, ALFRED C. FAIRBANKS.

